pearl vs seed pearl

pearl and seed pearl both are nouns.

Word	Noun	Adjective	Verb	Adverb
pearl	Yes	No	Yes	No
seed pearl	Yes	No	No	No

As nouns, seed pearl is a hyponym of pearl; that is, seed pearl is a word with a more specific, narrower meaning than pearl:

pearl: a smooth lustrous round structure inside the shell of a clam or oyster; much valued as a jewel
seed pearl: a small imperfect pearl

pearl (noun)	seed pearl (noun)
a shade of white the color of bleached bones	a small imperfect pearl
a smooth lustrous round structure inside the shell of a clam or oyster; much valued as a jewel
a shape that is spherical and small

pearl (verb)	seed pearl (verb)
gather pearls, from oysters in the ocean